EYES IN THE SKIES – EO/IR sensor turrets for UAVs
By David Maxwell
12 May 10. Over the past decade military forces, driven by events in Iraq and Afghanistan, have been playing catch-up in the surveillance game. ISTAR – Intelligence, Surveillance, Target Acquisition and Reconnaissance – capability has become the ‘Holy Grail’ and in 2010 it looks like the various efforts are beginning to come together. This is as much due to lateral thinking in the use of information gathered as the equipment used to gather it. One important element in the network of surveillance assets that have been brought into play has been the explosion of Unmanned Aerial Vehicles (UAVs) onto the military scene.
By their very nature, UAVs do not have an on-board pilot and so are deprived of that most basic of ISTAR sensors – the Mark One Mod Zero Eyeball! The alternative adopted has been the sensor turret and its associated image-gathering and distribution systems, which have evolved incredibly rapidly over the last five years from a pure surveillance tool to a sophisticated targeting system. The platforms themselves have also evolved, particularly in the ability to remain aloft for much longer, allowing the forces to improve an import element of ISTAR, especially when waging asymmetric warfare against an enemy that declines to wear uniform and can ‘melt’ away into the innocent civilian populace – persistent surveillance.
The use of unmanned aircraft for reconnaissance been around for well over 30 years – they were called “drones” then. I still remember visiting the Belgian firm of MBLE and being briefed on the Epervier artillery surveillance drone in 1977. The sensors then were wet-film cameras and the drone had to be safely recovered, the film developed and then prints made for physical distribution. It was a far cry from the digital imagery, much in full motion video (FMV), down-linked to ROVER terminals with the front line troops on patrol in real-time.
Today, UAVs range in size from micro-platforms with wingspans as small as 152mm to air vehicles the size of civil commuter aircraft. They can be fixed- or rotary-winged, including tilt-rotors, and, in addition to surveillance and targeting, they are being used, increasingly, as strike assets. While some UAV payloads include radar and signals intelligence (SIGINT) – usually of the communications intelligence (COMINT) flavour – it is the visual surveillance tool which virtually all platforms will have in addition to the other systems – the electro-optic/infrared (EO/IR) sensor turret on which this feature is focussed.
The industrial base for manufacturing UAVs is global, although it is products from Israel and the United States that dominate the market, with some French and German products beginning to make san impact. The EO/IR sensor turret industry (which serves helicopter and fixed-wing platforms as well as UAVs) offers equipment sourced from contractors in countries as diverse as Canada, France, Germany, Israel, South Africa, the UK and the United States. However, as many of the UAVs in operation today are of Israeli origin (either directly procured or built/developed under licence), let us look first at their contribution to the sensor turret market.
In terms of EO/IR systems, Controp Precision Technologies, Elbit Systems Electro-Optics (Elbit/Elop) and IAI Tamam produce such systems for ‘conventional’ UAV application, while Bental Industries produces the MicroBat series of EO payloads, weighing less than 350g, for installation aboard mini- and micro-UAVs.
Controp produces a wide range of UAV-applicable equipment that includes the smaller-than-1,000-g STAMP (STAbilised Miniature Payload) family of miniature EO payloads, the 12.3 kg ESP-600C colour observation payload, the 26 kg DSP-1 multi-sensor turret and the 28 kg FSP-1 forward-looking IR (FLIR) turret.
Within the STAMP range, there are six potential variants of this lightweight stabilised EO sensor: the two-gimbal dayl